A wide variety of medical diagnostic decision support systems are used in health care. These systems can generally record and process physiological data to present physiological features to assist a health care professional in determining the presence of a pathophysiological condition. One example of a medical diagnostic support system is an auscultation system that extracts features from a phonocardiogram. These auscultatory features are known in clinical practice and are readily understood by practicing physicians. Examples of such auscultatory features include the first heart sound (S1), second heart sound (S2), third heart sound (S3), fourth heart sound (S4), heart murmurs, S2 splitting, ejection sounds, opening snaps, and midsystolic clicks.
An objective of deriving physiological features such as auscultatory features is to provide the health care professional, such as a physician, with accurate information that can be used in making a diagnostic decision. At the primary care level, this typically depends on whether the physiological features are indicative of a condition necessitating a referral to a specialist for further evaluation.
Medical diagnostic decision support systems may attempt to identify specific features that are indicative of a specific pathophysiological condition. An auscultatory system, for example, may identify specific properties of a phonocardiogram that are consistent with a specific cardiovascular disease. This auscultatory system may be developed with the expectation that the physician would then refer for further evaluation patients with heart sounds that are generated by pathophysiological conditions.
The relationship between features extracted from physiological data and a diagnosis of a pathophysiological condition, however, is complex. It may be desirable to take into account additional information about the patient, such as medical history, symptoms, vital signs and the results of other tests, such as an X-Ray, electrocardiogram (EKG) in order to make a referral decision. By incorporating additional information, a physician may be better equipped to diagnose a pathophysiological condition, particularly if one of the examined features provides conflicting information as compared to the additional information. The additional information may be used to help reduce unnecessary referral decisions. It may also be desirable to automate a portion of the analysis used by physicians to make a referral decision. In this manner, a number of different information sources may be analyzed, integrated and presented to the physician for referral review.